<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    body{
      margin: 0;
      /* padding: 0; */
    }
    a{
      text-decoration: none;
    }

    ul{
      list-style: none;
      margin: 0;
      padding: 0;
    }

    .menu a{
      color: #b0b0b0;
       font-size: 12px; 
    }
    .menu .item{
      height: 40px;
      line-height: 40px;
      float: left;
      /* font-size: 12px; */
    }
    .container{
      width: 1226px;
      margin-left: auto;
      margin-right: auto;
    }

    .left{
      float: left;
    }

    .right {
      float: right;
    }

    .topbar{
      height: 40px;
      background: #333;
    }
    .topbar .container{
      height: 40px;
    }
    .left .item{
      margin-right: 5px;
    }
    .right .item{
      margin-left: 5px;
    }
  </style>
</head>
<body>
  <div class="topbar">
  <div class="container">
    <ul class="menu left">
      <li class="item"><a href="">菜单项1</a></li>
      <li class="item"><a href="">菜单项2</a></li>
      <li class="item"><a href="">菜单项3</a></li>
      <li class="item"><a href="">菜单项4</a></li>
      <li class="item"><a href="">菜单项5</a></li>
      <li class="item"><a href="">菜单项6</a></li>
      <li class="item"><a href="">菜单项7</a></li>
      <li class="item"><a href="">菜单项8</a></li>
      <li class="item"><a href="">菜单项9</a></li>
      <li class="item"><a href="">菜单项10</a></li>
      <li class="item"><a href="">菜单项11</a></li>
      <li class="item"><a href="">菜单项12</a></li>
      <li class="item"><a href="">菜单项13</a></li>
      </ul>

      <ul class="menu right">
        <li class="item"><a href="">菜单项1</a></li>
        <li class="item"><a href="">菜单项2</a></li>
        <li class="item"><a href="">菜单项3</a></li>
    </ul>
  </div>
</div>
</body>
</html>